Sinn Féin leader Gerry Adams has claimed his party colleague Martin Ferris was "held for several hours" by the authorities at Boston Airport.

Mr Ferris, a TD for Kerry and a convicted IRA gunrunner, is believed to have been stopped and questioned by immigration officials on Wednesday after arriving in the city to participate in events to mark St Patrick's Day.

The claim was made after Mr Adams launched a blistering attack on the officials after he was denied access to an event in the White House this week.

While his party colleagues Mary Lou McDonald and Martin McGuinness passed security checks at an event hosted by President Barack Obama, Mr Adams left after being made to wait for 90 minutes.

Sinn Féin have now alleged that their representatives have been subjected to "additional security procedures and delays" by the US authorities.

In a statement, Mr Adams said the party have raised its grievances with the US authorities in private in the past and that a review is now required.

"The constant additional security processes and delays which Sinn Féin representatives are regularly subject to has long been a cause of concern. We have raised it privately in the past, Mr Adams said.

"Yesterday, my colleague Martin Ferris was delayed getting on his flight to Boston and when he eventually arrived on a later flight he was held for several hours.

"In the course of my meeting with the State Department on Wednesday, during which they apologised for the White House situation, I urged the administration to review their approach to Sinn Féin representatives visiting the USA and to fulfil the commitment of the Clinton administration 20 years ago to normalise relations between the US administration and Sinn Féin."

Efforts to contact Mr Ferris proved unsuccessful last night, but a Sinn Féin spokesman said he was held up by immigration.

A spokeswoman for Boston Airport was unable to provide a response to Sinn Féin's claims before going to print.

On Tuesday, Mr Adams left the White House after he was delayed for 90 minutes for an additional security check on his arrival.

Ridiculed

After being refused entry, Mr Adams said there were "some in the US administration" who want to treat Sinn Fein differently and said his party will not "sit at the back of the bus for anyone".

He compared his exclusion to the civil rights icon Rosa Parks - a claim that was ridiculed by politicians back home.

Speaking in Brussels yesterday, acting Taoiseach Enda Kenny rejected the suggestions that Mr Adams was treated differently. "Rosa Parks was an international icon, a woman of courage and bravery who made a real mark on history, for its benefit," Mr Kenny said.

"I'm not going to comment on the difficulties with Deputy Adams getting into the White House. I understand the Secret Service have confirmed that they are apologetic as to what happened here but obviously everybody is treated the same going into the White House."

Following the incident at the White House, the US Secret Service released a statement saying the delay in processing Mr Adams was due to an "administrative input error".

"The Secret Service would like to express our regret that the issue involving Mr Adams's entry into the St Patrick's Day reception could not be resolved in a more timely manner. Unfortunately, an administrative input error received by the Secret Service was not able to be rectified promptly," it said.